Optical fibers are widely used in a variety of applications, including the telecommunications industry in which optical fibers are employed in a number of telephony and data transmission applications. Due, at least in part, to the extremely wide bandwidth and the low noise operation provided by optical fibers, the use of optical fibers and the variety of applications in which optical fibers are used are continuing to increase. For example, optical fibers no longer serve as merely a medium for long distance signal transmission, but are being increasingly routed directly to the home or, in some instances, directly to a desk or other work location.
With the ever increasing and varied use of optical fibers, it is apparent that efficient methods of coupling optical fibers, such as to other optical fibers, to a patch panel in a telephone central office or in an office building or to various remote terminals or pedestals, are required. However, in order to efficiently couple the signals transmitted by the respective optical fibers, a fiber optic connector must not significantly attenuate or alter the transmitted signals. In addition, the fiber optic connector must be relatively rugged and adapted to be connected and disconnected a number of times in order to accommodate changes in the optical fiber transmission path.
In order to provide the desired signal transmission characteristics, a number of fiber optic connectors have been developed which are mounted to the end portion of one or more optical fibers during a factory assembly process. By mounting the fiber optic connector to the optical fiber(s) and/or fiber optic cable (hereinafter optical fiber) during an assembly process at the factory, the assembly of the fiber optic connector can be standardized such that inconsistent assembly and other problems associated with the field installation of the connector are avoided.
However, the factory installation of fiber optic connectors is not altogether satisfactory for every application. In particular, the factory installation of fiber optic connectors does not customize the installation process to account for the myriad of design variations experienced in the field. For example, by installing fiber optic connectors to the end portion of an optical fiber at the factory, the length of the connectorized optical fiber is fixed, thus requiring excess length and coiling to insure sufficient length for all applications. In addition, in many instances, it is desirable to cut a length of optical fiber into a plurality of shorter lengths of optical fiber, each of which must be individually connected, such as by a fiber optic connector, to another optical fiber or to a patch panel or other type of terminal. However, the respective lengths of the shorter optical fibers cannot generally be determined until the optical fibers are installed in the field. Thus, in this instance, the requisite fiber optic connectors cannot be mounted to the fibers at the factory prior to installation of the optical fiber. Still further, it is desirable, in many instances, to package and ship optical fiber prior to the installation of the fiber optic connectors since the fiber optic connectors generally have a greater diameter than the respective optical fiber, and may unnecessarily complicate the packaging and shipping of the optical fiber.
Consequently, several fiber optic connectors have been developed which can be mounted to the end portion of an optical fiber in the field once the particular application of the optical fiber has been determined. For example, the UNICAM.TM. connector which is manufactured and distributed by Siecor Corporation, the assignee of the present invention, is adapted to be mechanically spliced to an optical fiber.
Unfortunately, the UNICAM.TM. connector as well as most other standard field installable connectors are designed to be mounted upon the end portion of a single optical fiber. Accordingly, in order to connectorize two or more optical fibers, such as provided by a fiber optic ribbon cable or the like, the optical fibers must be separated and then individually terminated with single fiber connectors. As will be apparent, the individual connectorization of a plurality of optical fibers therefore requires significant time, labor and cost. Additionally, the separation of a fiber optic cable into individual optical fibers also mechanically weakens the fiber optic cable at the point of separation.
In order to connectorize two or more optical fibers with a single connection, a number of multifiber connectors have been developed which receive and maintain two or more optical fibers in respective predetermined positions during interconnection. For example, the ESCON.TM. connector and the FCS.TM. connector have been developed. These connectors include a pair of conventional ferrules, each of which receive and maintain a single optical fiber in a predetermined position during interconnection. The ESCON.TM. and FCS.TM. connectors also include a housing or yoke which surrounds and supports the ferrules in a side-by-side relationship. Accordingly, these fiber optic connectors can provide for the simultaneous connection of two or more optical fibers as known to those skilled in the art. However, these fiber optic connectors, such as the ESCON.TM. and FCS.TM. connectors, have a nonstandard size and are generally relatively large since they include at least two conventional ferrules positioned in a side-by-side relationship. See also U.S. Pat. Nos. 4,898,449 to Vroomen, et al.; 5,064,268 to Morency, et al.; 5,093,881 to Bartolin, et al., 5,123,072 to Kawanami, et al.; and 5,125,055 to Kawanami, et al. which describe several other types of customized or nonstandard multifiber connectors.
Therefore, while a number of customized or nonstandard multifiber connectors have been developed, these multifiber connectors typically include multiple components, such as multiple ferrules, which must be assembled to form the fiber optic connector. Due to the multiple components which must generally be precisely aligned, the assembly process can be relatively complicated and the resulting cost of the nonstandard fiber optic connectors can be correspondingly increased. For example, the end face of most nonstandard multifiber connectors must be precisely polished since those multifiber connectors are typically quite sensitive to polishing imperfections which may result in poor optical performance or failure of the multifiber connector. As a result, specially trained technicians may be required to mount these multifiber connectors to the end portions of two or more optical fibers. In addition, due to the customized or nonstandard designs of these fiber optic connectors, the fiber optic connectors typically cannot mate with standard fiber optic connectors or with terminals which have been designed to mate with standard fiber optic connectors. As such, other connector hardware must be provided to permit these nonstandard multifiber connectors to mate with a connector sleeve, a terminal or the like. Further, the relatively large size of a number of the nonstandard fiber optic connectors described above limits the applications in which such fiber optic connectors can be employed since they may be unable to mate with other fiber optic connectors or other types of terminals in areas of limited access.